NMAT

Kinetochores

Kinetochores

protein structures located on the centromeres that serve as attachment points for specific fibers of the spindle apparatus (kinetochore fibers)

metastasis

distant spread of cancerous cells through the bloodstream or lymphatic systems

Mitosis

2 identical cells created from a single cell

Cytokinesis

splitting of cytoplasm and organelles into 2 daughter cells

Haploid (n)

cells that contain only 1 copy of each chromosome

example-germ cells

Diploid (2n)

contain 2 copies of each chromosome

Prophase (mitosis)

chromatin condenses into chromosomes

centriole pairs separate, move toward opposite sides of the cell, and form spindle fibers made of microtubules

the fibers radiate outward from the centrioles

nuclear membrane dissolves which allows spindle fibers to contact chromosomes

Metaphase

centriole pairs at opp. ends of cell

kinetochore fibers align chromosomes at the metaphase plate (equatorial plate) which is equidistant b/w 2 poles of the cell

Anaphase

centromeres split

each sister chromatic has its own distinct centromere

they are pulled toward opp. poles of cell

sister chromatids separate

Telophase and Cytokinesis

spindle apparatus disappears

nuclear membrane reforms around each set if chromosomes

nucleoli reappears

chromosomes uncoil

cytoplasm and organelles separate so that each daughter cell has supplies to survive on its own (cytokinesis)

results in 2 identical daughter cells

gametes

non-identical sex cells

Synapsis (Prophase I of Meiosis I)

homologous chromosomes come together and intertwine

Mendel's 2nd Law of Independent Assortment

inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes

Crossing Over

Chromatids of homologous chromosomes break at the chiasma and exchange pieces of DNA

occurs b/w homologous chromosomes not sister chromatids

allows each daughter cell to have a unique pool of alleles

Alleles

genes coding for alternative forms of a trait

Disjunction (anaphase I)

separation of homologous pairs, pulled to opp. poles of cell

Pathway of Sperm (Mnemonic --> SEVEN UP)

Seminiferous tubules, Epididymis, Vas Deferens, Ejaculatory Duct, Nothing, Urethra, Penis

Estrogen

secreted in response to FSH

thickening of lining of uterus (endometrium)

Progesterone

secreted by corpus luteum in response to LH

involved in development & maintenance of endometrium

Mitochondria

has 2 layers --> outer and inner membrane

outer membrane serves as barrier b/w cytosol and inner environment

inner membrane has infoldings (contains enzymes needed for e- transport chain)

Endoplasmic Reticulum

series of interconnected membranes folded into many invaginations

Smooth ER

-lacks ribosomes

-used for lipid synthesis, detoxification of poisons & drugs

-transport of proteins from RER to Golgi apparatus

Rough ER

-has ribosomes

-translation of proteins

Golgi apparatus

-stacked membrane bound sacs where cellular products are modified

-sorts and modifies products

-packages products in vesicles and transfers them to correct location

Peroxisomes

-contain hydrogen peroxide

-break down long chain fatty acids

cytoskeleton

-provides structure to cell/helps maintain shape

-3 components: microfilament, microtubules, intermediate filaments

Gram + Bacteria

-envelope absorbs crystal violet stain and appears deep purple

-have thick layer of peptidoglycan (made of AA and sugar)

-contain lipoteichoic acid (activates human's immune system so it provides protection from host's immune system)

Gram - Bacteria

-envelope absorbs safranin and appears pink-red

-contain smaller amount of peptidoglycan

-contains lipopolysaccharides (triggers immune system response in humans)

Episomes

-subset of plasmids capable of integrating into the genome of the bacterium

Conjugation

-2 cells form a conjugation bridge b/w them that allows for transfer of genetic material

-from donor male (+) to recipient female (-)

-the bridge is made from appendages called sex pili

-to form pilus, bacteria must contain plasmids called sex factors (Fertility factor (F))

F+ cell repliacates its F factor and donates a copy to the recipient converting it into F+ cell

Transduction

-requires a virus that carries genetic material from one bacterium to another (vector)

Zeroth Law of Thermodynamics

if object A is in thermal equilibrium with B and B is in thermal equilibrium with object C, then object A and C are also in thermal equilibrium

Third Law of Thermodynamics

entropy of a perfectly organized crystal at absolute zero is zero

First Law of Thermodynamics

the change in the total internal energy of a system is equal to the amount of energy transferred as heat to the system minus the amount of energy transferred as work from system

∆U=Q-W

second law of thermodynamics

objects in thermal contact and not in thermal equilibrium will exchange q heat energy such that object w/ higher temp. gives off heat energy to object w/ lower temp. until both objects have the same temp. at thermal equilibrium

Radiation

transfer of heat by electromagnetic waves

Motif

a repetitive organization of secondary structural elements

Actin

-structural protein

-makes up microfilaments & thin filaments in myofibrils

-have a + and - side

-polarity allows motor proteins to travel unidirectionally along actin filament

Motor Proteins

-Have enzymatic activity

- act as ATPases that power the conformational change needed for motor function

-have transient interactions with actin or microtubules

Myosin

-motor protein that interacts w/ actin

-thick filament in myofibril

-involved in cellular transport

-composed of head & neck

-neck movement causes power stroke of sarcomere contraction

Kinesin & Dynein

-motor proteins associated w/ microtubules

- have 2 heads

-at least 1 head remains attached to tubulin at all times

•Kinesins align chromosomes

•Dyneins involved in sliding movement of cilia & flagella

•Both important for vesicle transport

•Kinesins bring vesicles toward + end of microtubule & dyneins bring vesicles toward - end

Cell Adhesion Molecules (CAMs)

-proteins found on surface of most cells

-aid in binding the cell to the extracellular matrix or to other cells

Immunoglobulins (antibodies)

proteins produced by B-cells

neutralize targets (toxins, bacteria) in the body

recruit other cells to help eliminate the threat

Facilitated Diffusion

-type of passive transport

- diffusion of molecules down a concentration gradient through a pore in the membrane

Ungated Channel

-no gates, unregulated

-all cells have ungated potassium channels

Voltage Gated Channel

-gate regulated by membrane potential change near channel

-example: neurons have voltage gated sodium channels

Ligand-Gated Channel

the binding of a specific substance (ligand) to channel leads to transition in the protein causing it to open or close (neurotransmitters act at ligand gated channels at post-synaptic membrane)

Transduction (Behavioral Sciences)

-converts information from our internal and external environment to electrical signals in nervous system

-related to sensation

Sensory Receptors

-neurons that respond to stimuli & trigger electrical signals

Nociceptors

respond to painful or noxious stimuli

Osmoreceptors

-respond to osmolarity of the blood (water homeostasis)

Weber's Law

*there is a constant ratio b/w the change in stimulus magnitude needed to produce a jnd and the magnitude of the original stimulus

JND

*ex: jnd-3Hz, original- 40Hz

quantified as 3/40 = 0.68%

Signal Detection Theory

-perception of stimuli is affected by nonsensory factors like experience, motives, expectations

-perception of same stimuli changes depending on internal (psychological) and environmental context

Response Bias

-tendency of subjects to systematically respond to a stimulus in a particular way due to non-sensory factors (experience, motives, or expectations)

Trajectory of Sound

-Pinna --external auditory canal -- tympanic membrane --malleus -- incus -- stapes -- oval window -- perilymph in cochlea -- basilar membrane -- hair cells -- vestibulocochlear nerve -- brainstem -- MGN -- auditory cortex

Law of Proximity

-elements close to one another tend to be perceived as a unit

Law of Similarity

-objects that are similar tend to be grouped together

Law of Good Continuation

-elements that appear to follow in the same pathway tend to be grouped together

-We see continuous patterns rather than abrupt changes

Subjective Contours

-perceiving contours and shapes that are not actually present in the stimulus

Law of Closure

-when a space is enclosed by a contour it tends to be perceived as a complete figure

law of pragnanz

-conceptual organization will always be as regular, simple, and symmetric as possible

-regulate Gestalt Principles

Ectoderm

-outermost layer

-forms the integument (epidermis, hair, nails, epithelia of nose, mouth & lower anal canal, lens of the eye, nervous system including adrenal medulla & inner ear)

Mesoderm

-middle layer

-forms the musculoskeletal, circulatory & most of the excretory systems, gonads, muscular & connective tissue layers of digestive & respiratory systems, adrenal cortex

Selective Transcription

-only the genes needed for a particular cell type are transcribed

- allows for cells w/ same genes to develop into different cell types w/ highly specialized functions

Induction

-ability of one group of cells to influence the fate of other nearby cells

Morphocells

-molecules that may cause nearby cells to follow a particular developmental pathway

Autocrine Signals

-act on the same cell that secreted the signal

Paracrine Signals

-act on cells in the local area

Juxtacrine Signals

-cell directly stimulates receptors of adjacent cell

Endocrine Signals

-secreted hormones travel through the bloodstream to a distant target tissue

Reciprocal Induction

-occurs when 2 tissues induce further differentiation in each other

Cell Migration

-cells disconnect from adjacent structures & migrate to their anatomically correct location

Apoptosis

-programmed cell death

- cell divides into many self-containing pieces (apoptotic blebs) which are absorbed & digested by other cells

-blebs are contained by a membrane which prevents release of harmful substances after death into the extracellular environment

Necrosis

-cell death due to injury

-internal substances can be leaked

Tollen's Reagent

-detects presence of reducing sugar

-uses Ag(NH3)2+ as oxidizing agent

*in a + test, aldehydes reduce Ag+ to metallic silver

Benedict's Reagent

-detects presence of reducing sugar

-aldehyde group of an aldose is readily oxidized indicated by a red precipitate of Cu2O

Lactose

Glucose + galactose

Amylopectin

-type of starch

-contains branches via β-1,6 glycosidic bonds

-highly branched

-debranching enzymes degrade the polysaccharide chain

-more soluble due to branched structure

Amylose

-type of starch

- linear glucose polymer linked via α-1,4 glycosidic bonds

-long, straight

-degraded by α-amylase and β-amylase

Glycogen

-carbohydrate storage unit in animals

-has α-1,6 glycosidic bonds (1 for every 10 glucose molecules while amylopectin has 1 for every 25)

-highly branched which optimizes energy efficiency and makes it more soluble

Respiratory system

-mediated by changes in pressure

-During inspiration, there is a negative pressure gradient that moves air into lungs

-During expiration, there is a + pressure gradient that moves air out of the lungs

air>mouth>pharnyx>larnyx>trachea(epiglotis)>bronchi>bronchioles>alveolus

Habituation

-decrease in response after repeated exposure to the same stimulus

Dishabituation

- the recovery of a response to a stimulus after habituation has occurred

- occurs after a different stimulus has been presented

-refers to changes in response to the original stimulus not the new one

Associative Learning

-creation of a pairing or association either b/w 2 stimuli or b/w a behavior and a response

Spontaneous recovery

-weak conditioned response if an extinct conditioned stimulus is presented again after some time

Generalization

-stimulus similar enough to the conditioned stimulus can produce the conditioned response

-Little Albert's experiment --> conditioned to be afraid of a rat by pairing presentation of the rat with loud noise

also exhibited fear responses to similar things like white stuffed rabbit

Discrimination

-organism learns to distinguish b/w 2 similar stimuli

Behaviorism

-theory that all behaviors are conditioned

B. F. Skinner

Reinforcement

process of increasing the likelihood that an individual will perform a behavior

Escape Learning

-role of the behavior is to reduce the unpleasantness of something that already exists (like a headache)

Avoidance Learning

-meant to prevent the unpleasantness of something that has yet to happen (studying to avoid unpleasantness of poor score on MCAT)

Punishment

-uses conditioning to reduce occurrence of a behavior

Positive Punishment

-adds an unpleasant consequence in response to a behavior to reduce the behavior (thief arrested for stealing

meant to stop him from stealing again)

Fixed Ratio Schedules

-reinforce behavior after a specific number of performances of that behavior

-rat rewarded w/ food pellet every third time it presses a bar in its cage

Negative Punishment

-reduction of a behavior when a stimulus is removed (forbidding child from watching TV for bad behavior w/ goal of preventing the behavior from happening again)

Continuous Reinforcement

-type of fixed ratio schedule

-behavior is rewarded every time it is performed

Variable Ratio (VR) Schedule

- reinforce behavior after a varying number of performances of that behavior

- rat rewarded after 2 button presses, then 8, then 4

-Very Rapid for learning behavior

-Very Resistant to extinction

Fixed Interval Schedules

- reinforces the first instance of a behavior after a specific time period has elapsed

- rat gets a pellet every 60 seconds

-pressing the bar during those 60 seconds accomplishes nothing

Variable Interval Schedules

-reinforce a behavior the first time the behavior is performed after a varying interval of time

- rat waits 90 seconds to get a pellet after pressing but then has to wait 30 seconds to get another and then 3 minutes to get another pellet

Latent Learning

-learning that occurs w/o a reward but that is spontaneously demonstrated once a reward is introduced

-Rats carried through a maze and then incentivized w/ food reward for completing the maze performed better than (or same) rats who were trained to run the maze & rewarded along the way